Apparatus for forming material



Aug. 27, 1968 ZERNOW ET AL APPARATUS FOR FORMING MATERIAL Original Filed Sept. 18, .1981

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United States Patent 3,398,561 APPARATUS FOR FORMING MATERIAL Louis Zernow, Glendora, and Joseph Edberg, Covma, Calif, assignors to Aerojet-General Corporation, Azusa, Calif., a corporation of Ohio Original application Sept. 18, 1961, Ser. No. 138,959, now Patent No. 3,228,221, dated Jan. 11, 1966. Divided and this application Nov. 1, 1965, Ser. No. 535,615

6 Claims. (CI. 7256) This is a divisional application of copending application, Ser. No. 138,959, filed Sept. 18, 1961, now US. Patent 3,228,221 issued Jan. 11, 1966.

This invention relates generally to material forming, and more particularly to a new and improved method and apparatus for supplying shock energy to form material to a desired shape.

' Heretofore shock waves in a shock wave transmitting medium have been directed against material to be formed to force the material, usually metal, into a female die.

For material forming purposes, if the shape of the shock wave used to form the material can be controlled so it is generally similar and parallel to the shape of the female die into which the material is to be forced, the

number of shock waves required to perfectly form the material in the die will be minimized. Consequently, the forming operation will be quicker and less expensive.

However, the chemical explosives hereofore used to produce shock waves was often not satisfactory because of inherent limitations in the ability to control the intensity of the shock waves produced. Consequently, When chemical explosives are used in situations where the shock wave intensity cannot be closely regulated, there is danger of injury to the work and the formation of the material in the die requires more frequent explosive shock waves which are expensive and time-consuming.

In addition, depending for example on the chemical composition of the material to be formed, chemical explosives may not be suitable and other methods of supplying shock energy may be required.

What is needed, therefore, and among other things, comprises an important object of this invention, is to provide a method and apparatus for producing shock energy for material forming purposes without the use of chemical explosives.

Another object of this invention is to provide a means for forming a shock wave having any desired shape and intensity for use in material forming processes.

The invention in its broadest aspect comprises connecting a. source of electric energy across a thin wire or metal film positioned in a shock wave transmitting medium, gaseous or'liquid. The magnitude of the energy generated by the source is such that the wire or film explodes and produces a shock wave in the shock wave medium. This shock wave will have a shape related to the shape of the wire or film. Consequently, a shock wave having any desired shape can be produced by providing a suitably shaped wire or metal film. The intensity of the shock wave can be precisely controlled by regulating the magnitude of the electric energy source and the thickness of the metal film. The shock wave traveling through the medium impacts on the work, usually a metal blank, and this impact is sufiicient to force the work into a female die to form it. If the shock wave and the female die are generally similar in shape the metal blank can be formed in the die more perfectly.

These and other objects of this invention will become more apparent when read in the light of the accompanying drawings and specification, wherein:

FIG. 1 is a side sectional view of the apparatus utilizing the principles of this invention and showing the relation- 3,398,561 Patented Aug. 27, 1968 "ice ship between the metal wire to be exploded, the female die, and the work inside the liquid filled container;

FIG. 2a is a sectional view taken on the line 2a2a of FIG. 1;

FIG. 2b is a plan view of the interior of the container showing the configuration of the shock waves after the wires are exploded;

FIG. 20 is a sectional view of the apparatus utilizing the principles of this invention taken on the line 2c-2c of FIG. 1;

FIG. 3a is a perspective view of the female die used in the apparatus shown in FIG. 1; and

FIG. 3b is a perspective view of the work blank after his formed.

Referring now to FIG. 1 of the drawing, the material forming apparatus indicated generally by the reference numeral 10 comprises a container 12. This container is adapted to hold a shock wave transmitting medium such as water or other liquids or gases. For purposes of illustration, however, the container 12 in this particular embodiment is filled with water 14. A thin or small diameter conductive material indicated generally by the reference numeral 16 is placed in the container (see FIG. 2a). In the embodiment shown, the conductive material comprises a plurality of fine wires 18, 20, and 22. The opposite ends of these wires are connected to substantially thicker and electrically conductive support bars 24 and 26. These bars hold the wires 18, 20, and 22 in any predetermined spaced relation to each other. With this arrangement, the wires can be bent into any desired shape, for reasons to become apparent below. The electrically conductive support bars 24 and 26 are connected to an electric power source indicated generally by the reference numeral 28 by leads 27 and 29 and a control switch 30. The electrical power source may be a conventional circuit for changing a capacitor to a desired high voltage, or it could be an electrical generator with a large current capacity.

It is apparent that when switch 30 is closed, the electrical energy in power source 28 will be connected across the wires 18, 20, and 22. It has been found that if the magnitude of this electrical energy is sufficiently great, the wires will suddenly explode and form a shock wave in the water. It has further been found that the shape of the shock wave resulting from the explosion of the wires will be generally similar to the shape of the wire (see FIG. 2b), and the intensity of the shock wave will be related to the electrical energy in the power source. Consequently, elongated shock waves of any desired shape and intensity can be formed in the water by bending the fine wires 18, 20, and 22 to the shape desired. By way of specific example, it has been found that if a voltage in the range of 1200 to 1600 volts is suddenly connected across a conductive wire approximately .0005 inch in diameter, the wire will explode. Using these values for the voltage level in power source 28 and the thickness of wires 18, 20, and 22 when switch 30 is closed, wires 18, 20, and 22 explode and produce correspondingly shaped shock waves 31. It is apparent, however, that variations in the magnitude of the voltage or the source of electrical energy or the diameter of the wires or conductive material will control the size, shape, and intensity of the shock wave to be formed. In particular, it is contemplated that the wires could be formed from copper, aluminum, zinc, magnesium, tungsten, or other materials in sizes ranging from .0001 inch to A3 inch in diameter.

The material to be formed, which in this case, is a metal plate, indicated generally by the reference numeral 32 is laid over a female die 33 and is sealed thereon by sealing material 35a to prevent the entrance of the water or other liquid in the container into the interior of the 3,398,5fil

f 3 female die (see FIGS. 20 and 3a). In addition, the interior of the female die 33 is evacuated by means of the evacuation pipe 43 which is connected to a vacuum pump (not shown) to permit the impact of the shock wave on the metal blank to force the metal blank into the die.

The female die 33 rests on suitable supports 34 which are designed to hold the metal blank 32 in any suitable position in the container (see FIG. 1). This position is selected so that when the electrical wires 18, 20, and 22 explode, the impact of the shock waves on the surface of the metal blank 32 force it into the recesses 35, 37, and 39 in the female die, thereby producing correspondingly shaped impressions 36, 38, and 40 in the metal blank (see FIG. 3b).

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of the parts may be resorted to without departing from the spirit of this invention or the scope of the claims.

We claim:

1. An apparatus for forming an elongated impression in material having any desired shape, comprising in combination a container for holding a shock wave transmitting medium, wires mounted in the container and adapted to be connected to an electric power source, said electric power source having sufiicient magnitude to explode the wires and form a shock wave in said shock wave transmitting medium wherein the formed shock wave has a shape generally similar to the shape of the wires, a female die, said wires having a configuration generally similar to the shape of the female die and positioned so 4 4 t that the shock wave formed from the exploded wires'is generally parallel to the die, and means for holding the material to be formed in the container in such a position with respect to the wires so that when the electric power source is connected across the wires and explodes them, the resulting shock wave impacts on the material to be formed and forces it into thedie. p

2. The apparatus described in claim l wherein said wires are composed of copper .0001 inch to A; inch in diameter. 7 i

3. The apparatus describedin claim 1' wherein said wires are composed of aluminum .0001 inch to inch in diameter.

4. The apparatus described in claim 1 wherein said Wires are composed of zinc .0001 inch to A3 inch in diameter. I

5. The apparatus described in claim ,1 wherein said wires are composed of magnesium .0001 inch to A: inchin diameter. I s

6. The apparatus described in claim 1 wherein said wires are composed of tungsten .0001 inch to /8 inch in diameter. A

References Cited UNITED STATES PATENTS 2,935,038 5/1960 Chatten 72-56 3,163,141 12/1964 Wesley et a1. 72-56 FOREIGN PATENTS 119,435 3/1958 U.S.S.R.

RICHARD J. HERBST, Primary Examiner. 

1. AN APPARATUS FOR FORMING AN ELONGATED IMPRESSION IN MATERIAL HAVING ANY DESIRED SHAPE, COMPRISING IN COMBINATION A CONTAINER FOR HOLDING A SHOCK WAVE TRANSMITTING MEDIUM, WIRES MOUNTED IN THE CONTAINER AND ADAPTED TO BE CONNECTED TO AN ELECTRIC POWER SOURCE, SAID ELECTRIC POWER SOURCE HAVING SUFFICIENT MAGNITUDE TO EXPLODE THE WIRES AND FORM A SHOCK WAVE IN SAID SHOCK WAVE TRANSMITTING MEDIUM WHEREIN THE FORMED SHOCK WAVE HAS A SHAPE GENERALLY SIMILAR TO THE SHAPE OF THE WIRES, A FEMALE DIE, SAID WIRES HAVING A CONFIGURATION GENERALLY SIMILAR TO THE SHAPE OF THE FEMALE DIE AND POSITIONED SO THAT THE SHOCK WAVE FORMED FROM THE EXPLODED WIRES IS GENERALLY PARALLEL TO THE DIE, AND MEANS FOR HOLDING THE MATERIAL TO BE FORMED IN THE CONTAINER IN SUCH A POSITION 